Magneto-Refractive Effect and Sensing Characteristics of Erbium-Doped Silica Fiber

The magneto-refractive sensing characteristics of erbium-doped silica fiber (EDF) demonstrate significant potential for magnetic field sensing in harsh environments. The refractive index (RI) distribution with different magnetic fields of EDF is investigated. The experiment shows that the RI changes of EDF core region is linear to the magnetic field, the magneto-refractive sensitivity of EDF is
$\boldsymbol{-4.60\times 10^{-4}\text{RIU}/\text{mT}}$
, which is about three orders of magnitude higher than the single mode fiber (SMF). All solid EDF magneto-refractive sensing measurement system was constructed to detect weak alternating current (AC) magnetic fields. The magnetic field sensing sensitivity in AC magnetic field (500Hz) was measured as
$\boldsymbol{4.914\times 10^{-5}\text{rad}/\mu \mathrm{T}}$
with a resolution of 0.37
$\mu \mathbf{T}/\surd\mathbf{Hz}$
. The EDF magneto-refractive sensor has good linearity and high magnetic field sensitivity and shows development prospect in all-fiber weak magnetic field detection.